Method of forming low temperature dispersions

Abstract

Dispersions with lowered freezing points are provided by dissolving a dispersing agent in water, adding urea, adding a particulate inorganic solid, and then adding alcohol as a freezing point depressant. Dispersions formed in this manner can contain 20 to 75% inorganic solids in suspension without flocculating in the presence of the alcohol. Alternatively, the dispersant can be dissolved in an aqueous urea solution and the fine, particulate inorganic solid can be dispersed in the solution after which the alcohol may be added. These compositions exhibit depressed freezing points and can still be transported as a liquid at lower temperatures.

What is claimed is: 
     
       1. A method of forming an aqueous dispersior of solid particles having a depressed freezing point, comprising the steps of: dissolving a condensed phosphate dispersant in water in an amount equal to 0.2 to 4.0% by weight of solid particles to be added;   mixing urea into the water containing the dispersant in an amount equal to 3 to 30% by weight of the dispersion;   adding solid particles to the mixture in an amount equal to 20 to 75% by weight of the dispersion; and   adding an antifreeze solution selected from the group consisting of methanol, ethanol, isopropanol, ethylene glycol and propylene glycol to the dispersion in an amount equal to 9 to 30% by weight of the dispersion to depress the freezing point of the dispersion without flocculating the solid particles.   
     
     
       2. A method as described in claim 1, wherein the solid particles comprise a clay selected from the group consisting of sepiolite, attapulgite, palygorskite and kaolin. 
     
     
       3. A method as described in claim 1, wherein the solid particles are selected from the group consisting of calcium carbonate and titanium dioxide. 
     
     
       4. A method of forming an aqueous dispersion of solid particles having a depressed freezing point, comprising the steps of: mixing urea into water in an amount equal to 3 to 30% by weight of the dispersion;   dissolving a condensed phosphate dispersant in the urea water mixture in an amount equal to 0.1 to 4.0 by weight of the solid particles to be added;   adding solid particles to the mixture in an amount equal to 20 to 75% by weight of the dispersion; and   adding an antifreeze solution selected from the group consisting of methanol, ethanol, isopropanol, ethylene glycol and propylene glycol to the dispersion in an amount equal to 9 to 30% by weight of the dispersion to depress the freezing point of the dispersion without flocculating the solid particles.   
     
     
       5. A method as described in claim 4, wherein the solid particles comprise a clay selected from the group consisting of sepiolite, attapulgite, palygorskite and kaolin. 
     
     
       6. A method as described in claim 4, wherein the solid particles are selected from the group consisting of calcium carbonate and titanium dioxide.